364 SECTIONAL TRANSACTIONS.—K. 
3. Australian: Myrtaceew, Proteaceew, Goodeniacee, Chenopodiacee, Epacridacee 
and Rutacee forming 11-32 per cent., and in the first 14-17 Families. 
4. South African: Iridacew, Ficoidacee, Hricacee, Crassulacew, Geraniacee 
and Rutacee forming 15-20 per cent., and in the first 18-20 Families. 
The analyses serve to check Floral Regions based*on other criteria. They are 
consistent with the hypothesis of a former wider distribution of Families, under 
relatively uniform genial climatic conditions, with subsequent climatic and floristic 
segregation. 
AFTERNOON. 
Excursion to Hurst Castle. 
Wednesday, September 2. 
Mornine. 
25. Dr. W. L. Batts, F.R.S., and Mr. H. A. Hancock. — Problems 
presented by the Growth of Seed-hairs. 
The seed hairs of cotton show various structural peculiarities, which are evidently 
impressed during the growth of the hair in length. They show no signs of ordinary 
environmental control, nor are there any genetic differences from one cotton to 
another. The material is inconvenient for growth studies, but otherwise almost ideal 
for the recognition of cell individuality in a large homogeneous population of 
single cells. 
26. Mr. and Mrs. H. Hamsnoaw Tuoomas.—On the Ancestry of the 
Caytoniales. 
Assuming that the Sagenopteris type of leaf belonged to the plants whose repro- 
ductive structures are characteristic of the group Caytoniales, and that the structures — 
known suggest deviation from Pteridosperm ancestors, we may inquire whether such ~ 
ancestors can be found among Paleozoic plants. In leaf-form Sagenopteris closely 
resembles the Glossopteris alliance, among which there are several little-known but 
very interesting leaf-types. The reproductive structures of Glossopteris are still un- — 
known. The sporangium-like organs found in association with it have been ~ 
re-investigated and prove to be more like ramental scales than sporangia. At the 
same time, seeds and winged pollen grains closely similar to those of the Caytoniales — 
have been found associated with Glossopteris in some fine-grained shales from Natal. — 
It is probable that Glossopteris was a Pteridosperm, and it is possible that from this — 
stock the Caytoniales and also the flowering plants have been derived. ; 
27. Mr. J. Line.—Soluble Aluminium in Relation to Plant Growth in 
Culture Solutions and in Acid Soils. 
1. The evidence on which the ‘ toxic aluminium ’ theory of acid soils is based. 
2. The conditions under which aluminium is precipitated as hydroxide and as 
phosphate. 
3. The addition of aluminium salts to culture solutions ; interaction of plant and 
such culture solutions. 
4. Amounts of soluble aluminium found in acid soils, and the growth of plants in 
soils so treated. 
Tee ce 
28. Prof. A. H. R. Buttur.—The Phenomenon of Puffing in Sarcoscypha 
protracta and other Discomycetes. : 
29. Mr. N. J. G. Smiru.—The Life-history of some Parasitic Species of 
. . 1 
Helminthosporium. : 4 
H. gramineum, which causes leaf-stripe disease of barley, has hitherto been con- 
sidered to inhabit the growing-point of the host, and thence to infect all the young 
parts of the plant as they are formed. It is now shown that each leaf is infected from _ 
